Donald Trump is a man of many words, but it really would be better if he kept his mouth shut.

As The Washington Post reports, on Saturday the presidential candidate set his sights on Senator John McCain, who spent over five years as a prisoner of war after his plane was shot down during combat in Vietnam.

"He's not a war hero," said Trump, who avoided the draft with a series of deferments, during the Family Leadership Summit. "He's a war hero because he was captured. I like people that weren't captured."

The day prior, The New Yorker published an interview with McCain in which the Arizona Senator got candid about Trump's campaign. "It's very bad," McCain said, noting he was particularly upset with Trump's rally in Arizona. "This performance with our friend out in Phoenix is very hurtful to me," he explained. "Because what he did was he fired up the crazies."

Trump, who endorsed McCain, in 2008, lashed out at the senator on Twitter and Facebook.

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I am not a fan of John McCain because he has done so little for our Veterans and he should know better than anybody what...

Posted by Donald J. Trump on Saturday, July 18, 2015

Many Republican politicians shared their support of McCain and criticized Trump's remarks, including the Republican National Committee.

"Senator McCain is an American hero because he served his country and sacrificed more than most can imagine. Period," RNC Chief Strategist and Communications Director Sean Spicer said in a statement. "There is no place in our party or our country for comments that disparage those who have served honorably.

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But maybe the best response to Trump came from Mitt Romney, who ran against McCain in the 2008 GOP primaries.